2 x 1 mL (200 rxns of 20 µL)
20 x 1 mL (2000 rxns of 20 µL)
5 x 1 mL (500 rxns of 20 µL)
For 3 x 0.5 ml (150 rxns of 20 µL)
5 x 1 ml
1 mL (100 rxns of 20 µL)